/*
 * Copyright (c) 2007-2012, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
/*
 * Copyright 1999-2004 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id: FuncNamespace.java,v 1.2.4.1 2005/09/14 20:18:46 jeffsuttor Exp $
 */
package com.sun.org.apache.xpath.internal.functions;

import com.sun.org.apache.xml.internal.dtm.DTM;
import com.sun.org.apache.xpath.internal.XPathContext;
import com.sun.org.apache.xpath.internal.objects.XObject;
import com.sun.org.apache.xpath.internal.objects.XString;

/**
 * Execute the Namespace() function.
 * @xsl.usage advanced
 */
public class FuncNamespace extends FunctionDef1Arg {
    static final long serialVersionUID = -4695674566722321237L;

    /**
     * Execute the function.  The function must return
     * a valid object.
     * @param xctxt The current execution context.
     * @return A valid XObject.
     *
     * @throws javax.xml.transform.TransformerException
     */
    public XObject execute(XPathContext xctxt) throws javax.xml.transform.TransformerException {

        int context = getArg0AsNode(xctxt);

        String s;
        if (context != DTM.NULL) {
            DTM dtm = xctxt.getDTM(context);
            int t = dtm.getNodeType(context);
            if (t == DTM.ELEMENT_NODE) {
                s = dtm.getNamespaceURI(context);
            } else if (t == DTM.ATTRIBUTE_NODE) {

                // This function always returns an empty string for namespace nodes.
                // We check for those here.  Fix inspired by Davanum Srinivas.

                s = dtm.getNodeName(context);
                if (s.startsWith("xmlns:") || s.equals("xmlns"))
                    return XString.EMPTYSTRING;

                s = dtm.getNamespaceURI(context);
            } else
                return XString.EMPTYSTRING;
        } else
            return XString.EMPTYSTRING;

        return ((null == s) ? XString.EMPTYSTRING : new XString(s));
    }
}
